Internal signals in an integrated circuit are often generated and transmitted as differential signals to reduce the effects of noise. Differential signals are sent over two lines such that a positive change in voltage in a first line is mirrored by a negative change in voltage in a second line. The state of an internal signal is determined from a voltage difference between the first and second lines. Noise picked up by the first and second lines is substantially the same and does not significantly interfere with the determination of the state of the internal signal.
The generation and transmission of differential signals in an integrated circuit requires more circuitry than would be needed to support single-ended signals. A single-ended signal is a signal sent over a single line. When a differential internal signal is to be transmitted to another integrated circuit it is often desirable to translate the differential internal signal into a single-ended signal before transmission outside the integrated circuit. This is done because the number of external pins dedicated to the integrated circuit and the number of lines available in a bus for transmitting signals from the integrated circuit can be limited.